title: Co-expression of CD44 and ABCG2 in spheroid body-forming cells of gastric cancer cell line MKN45.
abstract: OBJECTIVE
  The cancer stem cell (CSC) theory hypothesizes that CSCs are regarded as the cause of tumor formation, recurrence and metastasis. This study aimed to investigate whether spheroid body-forming cells in human gastric cancer cell were enriched for CSC properties, and to assess the expression of candidate CSC markers, cluster of differentiation 44 (CD44) and adenosine triphosphate binding cassette transporter G 2 (ABCG2) in the MKN45 spheroid body cells.
  
  
  METHODS
  Human gastric cancer cell line MKN45 were plated in stem cell conditioned culture system allowed for spheroid body forming. The expression levels of CD44 and ABCG2 in the spheroid body cells were assessed by quantitative real-time PCR, western blot analysis and immunofluorescence staining, and the tumorigenicity of the spheroid body-forming cells were assessed by in vivo xenograft studies in nude mice.
  
  
  RESULTS
  The MKN45 cells could form spheroid bodies cultured in stem cell conditioned medium. The spheroid body-forming cells showed a significantly greater (p <0.05) expression of CD44 and ABCG2 than the parental cells.
  
  
  CONCLUSIONS
  Spheroid body cells from gastric cancer cell line MKN45 cultured in stem cell conditioned medium possessed gastric CSC properties. The cells co-expressed of CD44 and ABCG2 might represent a subpopulation of gastric CSCs.
authors.forename: Jianming
authors.initials: J
authors.lastname: Liu
authors.forename: Lilin
authors.initials: L
authors.lastname: Ma
authors.forename: Junfei
authors.initials: J
authors.lastname: Xu
authors.forename: Chun
authors.initials: C
authors.lastname: Liu
authors.forename: Jianguo
authors.initials: J
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Ruixin
authors.initials: R
authors.lastname: Chen
authors.forename: Youlang
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000032:analysis*; D000818:Animals; D045744:Cell Line, Tumor; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000032:analysis*; D014411:Neoplastic Stem Cells / Q000737:chemistry*; D018874:Spheroids, Cellular / Q000737:chemistry*; D013274:Stomach Neoplasms / Q000737:chemistry / Q000473:pathology*
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; C497483:CD44 protein, human; D018960:Hyaluronan Receptors; D009363:Neoplasm Proteins